The book is a prose recounting of myths and stories from three eras: Greek and Roman mythology, King Arthur legends and medieval romances. Bulfinch intersperses the stories with his own commentary, and with quotations from writings by his contemporaries that refer to the story under discussion. This combination of classical elements and modern literature was novel for his time.[2]

Bulfinch expressly intended his work for the general reader. In the preface to The Age of Fable he states "Our work is not for the learned, nor for the theologian, nor for the philosopher, but for the reader of English literature, of either sex, who wishes to comprehend the allusions so frequently made by public speakers, lecturers, essayists, and poets, and those which occur in polite conversation."[3]

Bulfinch originally published his work as three volumes: The Age of Fable, or Stories of Gods and Heroes, published in 1855; The Age of Chivalry, or Legends of King Arthur, published in 1858; and Legends of Charlemagne, or Romance of the Middle Ages, published in 1863. The original three volumes were later combined into a single volume titled Bulfinch's Mythology.[4] Now in the public domain, multiple editions of the combined work are still in print more than 150 years after the three books were published.